Visual voicemail (VVM) is a user friendly application that adds a visual aspect to managing voicemail messages. Traditional telephone user interface (TUI) voicemail requires users to dial into a system to listen to voicemails in a sequential order. VVM may enable mobile phone users to manage voicemail message in an order of their choice, e.g., in a random order rather than a sequential order.
VVM and some voicemail systems may be associated with one or more notification servers that notify mobile phone users about new (or not retrieved) voicemail messages. The notification servers serve as a gateway between the VVM/voicemail systems and mobile phones. The notification servers receive messages from the VVM/voicemail systems through bindings created by the VVM/voicemail systems, and the notification servers create notifications based on the messages and/or bindings. A binding may include a reference (e.g., an identifier) to something (e.g., a value, a machine address, etc.) that is larger or more complicated than the reference. For example, a binding may use a simple identifier (e.g., “AA”) to designate a more complicated machine address (e.g., “00010000111100001”). A binding may also provide information that instructs a notification server to create notifications and to send the notifications to particular user devices at particular times.
The bindings created by the VVM/voicemail systems are not load balanced. For example, some notification servers may receive a large number of bindings, while other notification servers may receive a smaller number of bindings. Due to unbalanced bindings among the notification servers, messages and/or notifications may be queued on some of the notification servers, which may cause significant delays. Furthermore, if a notification server is not operational, it will not receive messages when it becomes operational until the bindings are reset. Additionally, when a new notification server is added, the new notification server will not receive messages until a binding is created, which may take a considerable period of time (e.g., especially for third party voicemail systems).